RU2324604C2 - Method of production of large items of natural amber - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: method of production of large items of natural amber includes feeding of raw material cleared from oxides and impurities into the matrix of hermetic mould, heating and pressing followed by cooling, grinding and polishing of the item. The mould is heated to 260-300°C. Compressing is performed in several stages. At the first stage pressure up to 500 kg/cm is applied followed by fixation of the pressure with simultaneous cooling of the compression mold. During cooling matrix to 180°C pressure 800 kg/cm is applied providing surface diffusion of amber pieces.

EFFECT: invention allows obtaining high quality items with preservation of amber structure and physical properties of amber.

4 cl, 5 dwg

Description

The invention relates to methods for processing amber and obtaining large-format products.

The aim of the invention is to increase the utilization of amber without the use of any synthetic or natural impurities. Natural raw amber of various sizes and shapes is used as a raw material: large pieces of amber, amber pebbles, fragments of amber, defective amber products, previously washed and skinned.

Thus, the coefficient of amber use is increased due to the processing of cheap amber raw materials and waste products of amber products.

A known method of processing amber (RF Patent No. 2173258, MKI 7 B28D 5/00), in which the amber raw material is loaded into the working chamber, which is sealed, the raw material is heated, aged and cooled naturally, while compressing, filtering and removing thermal degradation products is carried out by evacuating the working chamber throughout the entire technological cycle.

In this case, the pressing of raw materials is carried out by retracting the elastic shell.

The disadvantage of the above method is the inability to use to obtain products of complex three-dimensional forms.

A method of manufacturing decorative products from natural amber (RF patent No. 2240925, MKI 7 V44B 5/06), which consists in the fact that the pressing of the heated feedstock in a vacuum mold is carried out with simultaneous depressurization and the termination of evacuation with preliminary heating of the raw materials and press form, as well as loading less or more raw materials in comparison with the required fixed volume of the matrix form, does not seem to work, because does not allow to obtain durable and high-quality products, and in its main part (heating of raw materials and molds) it repeats the patent of the Russian Federation No. 2191704, MKI 7 V44C 5/06, "Method for the manufacture of large-format products from a fine fraction of natural amber", which is the closest to the proposed method. It provides for the selection of pieces of amber with a certain size of fractions, a certain shape and color, heating the raw material to a temperature of no higher than 140 ° C and pressing with a gradual increase in pressure from 0 to 100 atmospheres with holding force for a specified period of time, cooling naturally, followed by grinding and polishing the finished product. However, this method is carried out after a strict selection of amber raw materials by color, shape and size.

The proposed method allows to obtain large-format amber products of complex volumetric form by mutual surface diffusion of amber pieces by pressing (pressing) in a special mold with subsequent manual refinement (grinding, polishing). In this case, raw materials of various shapes and sizes can be used, the main thing is that there are no foreign inclusions (sand, earth, etc.).

To obtain high-quality products, accurate uniform heating of the raw material during the pressing process is very important. For this purpose, a special design mold is used, and an electronic thermocouple is used for accurate temperature control.

Depending on the shape of the product, its geometry, calculate the "stroke" of the punch, the heating temperature of the mold. The pressure supply mode is also selected for each specific product and is carried out in several stages. Determining the quality of the product is the first stage of applying pressure from 0 to the moment of formation of the geometry of the product inside the matrix, i.e. up to about 500 kg / cm ² . All subsequent pressure adjustments are intended to maintain the effect of pressure. Such a "pressing" of amber is necessary, because during cooling, amber decreases in volume, pressure drops, and the product may lose its shape. At the same time, excessive “crushing” will lead to the formation of excessive internal stress, which is manifested in the increased fragility of the product during its further processing.

"Underfilling" will lead to the preservation of air in the mold and structure, which is a defect, therefore, it is important to calculate the values of pressure and heating temperature of the product of each form.

When loading raw materials, depending on the shape and size of the desired product, you can apply several options for technological operations.

1 option. Heating of the raw materials in the matrix together with the mold without air access. Cold raw materials are loaded into a cold mold, then the evacuated mold is heated, and therefore, the raw materials in the muffle furnace. In this case, the punch may be in the working volume of the mold or heated separately, and then carry out pressing.

Option 2. Cold raw materials are loaded into a pre-heated matrix (form) to 30-60 ° C, which is closed to prevent air from entering and placed in a muffle furnace for further heating to operating temperatures. There is no pressure (Punch in parallel).

3 option. Amber raw materials are heated with stirring for uniform heating and color control. At the right time, the heated amber is loaded into the matrix and pressed.

In each embodiment, the cooling of the product occurs in a pressed state. At the same time, additional air or water cooling can be used to accelerate the cooling process. However, the cooling should not be too intense, because this can lead to fragility of the product.

Figure 3 presents one of the possible variants of the device for implementing the inventive method.

The mold consists of a guide 1, a matrix 2 with holes for venting air and amber degradation products 6, while the configuration of the inner wall of the matrix determines the shape of the outer surface of the product, punch 3, the outer surface of which is made according to the shape of the outer surface of the manufactured product. In the lower part of the matrix 2 is provided a cylindrical bottom insert 4 reverse. In order to protect the working surface of the punch from damage (dents, chips) in the upper part of the working surface of the guide, a ring 5 of soft metal (for example, aluminum) is mounted. Moreover, the design of the mold, depending on the design of the product and its geometric shape, as well as for the purpose of more convenient extraction of the product from the matrix, can be collapsible-extruding, collapsible-punching out or combined.

The mold is made by turning and milling of metal of a certain brand, which, when quenched to 55 units and during subsequent heating in production, should not be “released". In this case, the working surface of the matrix is polished and chrome-plated, in addition, it can be coated with a gel (for example, silicone grease for molds during heat treatment TU 2389-016-455-11-510-99).

In all cases, air and amber degradation products are removed from the matrix through the openings 6 located in it, in addition, a groove 7 is made on the matrix (Fig. 4). Such a groove 7 may be located on the punch 3 (figure 3). The purpose of the groove is the accumulation of excess processed raw materials, this blocks the path to the non-working area of the guide. The presence of a groove greatly facilitates the removal of the finished product, eliminates the marriage of the product and reduces mold wear.

A method of manufacturing large-format products from natural amber according to the invention is as follows. The necessary amount of the raw material purified from oxides and impurities is measured by weighing on a balance. Parts of a sealed mold: a punch guiding with a die, covered with a “thermal jacket” (not shown) is placed in a muffle furnace and heated to a temperature of 260-300 ° C. "Thermo shirt" is used to uniformly heat up the matrix and is a metal cylinder of such height and diameter that would be sufficient to cover the mold matrix. After warming up, the mold is removed from the furnace, the “thermo shirt” is removed, the raw materials are poured into the die, the punch is installed and the mold is placed in the press, where it is subjected to pressure. Pressing can be carried out with a hydraulic press with a manual drive for a smooth pressure supply. Initially, pressure is applied from 0 to ~ 500 kg / cm ² . This pressure is recorded while cooling the mold (using natural or forced cooling). At the same time, the temperature of the matrix is measured using a thermocouple. When the matrix is cooled to a temperature of 180 ° C., a second pressure stage of 800 kg / cm ^{2 is} supplied. Amber pieces heat up, acquire plasticity and form the product defined by the mold by mutual surface diffusion. Upon heating, the amber mass increases in volume and fills the entire mold-forming volume of the matrix, and excess amber raw materials are removed through the holes 6 provided for this in the matrix 2. In addition, excess raw materials are collected in the groove 7 made on the matrix or on the punch in diameter or perimeter depending on their shape.

The process of phased pressure can be illustrated in figure 1.

In order to obtain products with a transparent structure after the first pressure stage, it is reset to zero (in this case, the internal stress in the formed raw material is relieved) and the next pressing stage is performed in accordance with the matrix temperature.

This process can be illustrated in figure 2.

When the mold is cooled to 80 ° C, the pressure is removed, the mold is disassembled and the product is removed.

For the manufacture of the required shapes of products, molds of various designs are used.

Figure 3 presents a mold that allows pressing by direct pressing. In this case, after pressing, the punch 3 is removed, the bottom insert 4 is pressed out, which pushes the finished product. The matrix is solid.

Figure 4 shows the mold with a collapsible matrix and collapsible punch. It consists of a guide 1 with a protective ring 5, a matrix 2, consisting of two parts with holes 6 made on it to remove amber degradation products and a groove 7, a punch 3 consisting of a rod and “petals”. The matrix is made collapsible to facilitate the removal of the finished product after the pressing process, and the collapsible punch allows you to perform products with a complex internal shape (for example, cognac glass). Only a collapsible punch design allows it to be removed from the finished product, because its “neck” is already on the bottom surface formed by the punch.

Figure 5 presents a collapsible punch consisting of a rod 1, "petals" 2, fastened together by grooves such as "dovetail" and screws 3.

After the process of pressing and cooling the product, the mold is disassembled, freeing the finished product with a punch. Then the screws 3 are unscrewed, the rod 1 is removed, after which the "petals" 2 are separated, which are removed one from the product.

Thus, the use of stepwise pressing while cooling the mold allows you to get high-quality amber products of any fraction, without the use of artificial or natural additives, and a collapsible punch design provides the ability to manufacture products of complex shapes. In this case, preliminary grinding of amber to a powder state is not required, due to which its structure, and therefore its physical and aesthetic properties, is preserved.

Claims (4)

1. A method of manufacturing large-format products from natural amber, including loading purified raw materials from oxides and impurities into an airtight mold matrix, heating and pressing, followed by cooling, grinding and polishing the resulting product, characterized in that the mold is heated to a temperature of 260 -300 ° C, and the pressing is carried out in several stages with the supply at the first stage of pressure up to 500 kg / cm ² and then fixing the pressure while cooling the mold, while cooling the mat eggs up to 180 ° C supply pressure of 800 kg / cm ² , ensuring mutual surface diffusion of amber pieces. 2. The method according to claim 1, characterized in that during pressing, the temperature of the mold is heated. 3. The method according to claim 1, characterized in that when heated to achieve uniform heating of the mold matrix. 4. The method according to claim 1, characterized in that forced cooling is used during the pressing process.

Images